Method for connecting a terminal fitting and a flat conductor, a terminal connection apparatus and a terminal fitting

ABSTRACT

A method is provided for connecting a terminal fitting and a flat conductor to achieve a high contact pressure between the terminal fitting and a conductive path. A FFC ( 10 ) has an insulation sheet ( 12 ) adjacent the end stripped to expose a conductor ( 11 ). The FFC ( 10 ) is inserted between first and second squeezing plates ( 22, 23 ) of a terminal fitting ( 20 ). Complimentary recessed/projected portions ( 32, 33 ) are formed on the outer surfaces of a pair of upper and lower press dies ( 30, 31 ) for pressing the terminal fitting ( 20 ). The terminal fitting ( 20 ) is pressed by the press dies ( 30, 31 ). Thus, the FFC  10  and the terminal fitting ( 20 ) are pressed together into a single unit and the squeezing plates ( 22, 23 ) are formed into a zigzag configuration.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a terminal fitting for a flatconductor, a method for connecting a terminal fitting to a flatconductor and a terminal connection apparatus.

[0003] 2. Description of the Related Art

[0004] Flexible flat cables (FFCs) and flexible printed circuit boards(FPCs) are referred to generally as flat conductors. The FFC is aribbon-shaped structure formed from a plurality of parallel conductorsand insulation sheets adhered to the front and rear surfaces of theconductors. There are two methods for connecting terminal fittings withthe respective conductors near the end of an FFC. The first methodconnects the terminal fittings while the conductors are left imbedded inthe insulation sheets. The second method, on the other hand, strips theinsulation sheet off one surface near the end of the FFC, and thenconnects the terminal fittings with the conductors.

[0005] The second method is disclosed in Japanese Utility ModelPublication No. 63-73861 and is shown in FIG. 7 of this application.With reference to FIG. 7, the second method starts with an FFC 1 thathas an insulation sheet 2 on the front and rear sides of conductors 3. Aportion of the insulation sheet 2 is stripped for a specified distancefrom an end of the FFC 1 to expose the front sides of the conductors 3.The second method then uses a terminal fitting 4 with a connectingportion 5 and a first squeezing plate 6 that extends from the rear endof the connecting portion 5 for connection with a mating terminalfitting (not shown). The terminal fitting 4 also has a second squeezingplate 7 with a base end 7A that is integral with the base end of thefirst squeezing plate 6. The second squeezing plate 7 can be pivotedabout the base end 7A to close and open with respect to the firstsqueezing plate 6. Crimping pieces 8 are formed at opposite edges of theleading end of the second squeezing plate 7 and extend toward the firstsqueezing plate 6. The terminal fitting 4 and the FFCI are connected bysqueezing the conductor 3 between the squeezing plates 6 and 7.

[0006] The second method merely brings the flat second squeezing plate 7into surface contact with the conductor 3. Thus, contact pressure isinevitably low, and the electrical contact is not reliable.

[0007] The present invention was developed in view of the above problem,and an object of the invention is to provide a method and apparatus forconnecting a terminal fitting and a flat conductor as well as a terminalfitting which secure a high contact pressure between the terminalfitting and a conductor.

SUMMARY OF THE INVENTION

[0008] The invention is directed to a method for connecting a terminalfitting with a flat conductor. The method comprises exposing a conductornear an end of the flat conductor. The method then comprises arrangingat least one pair of squeezing plates of the terminal fitting to atleast partly oppose each other at the front and rear sides of theexposed conductor. The method further comprises deforming a portion ofthe squeezing plates into a deformed configuration. The exposed endportion of the flat conductor then is squeezed by the squeezing plates.Thus, the squeezing plates are deformed into a zigzag configuration andthe squeezing plates squeeze the exposed end portion of the flatconductor.

[0009] At least one squeezing plate may include at least one holdingportion for holding the squeezing plates in a condition where theexposed conductors of the flat conductor are squeezed between thesqueezing plates. The holding portion on one squeezing plate may be bentinwardly and crimped into connection with the other squeezing plate.Thus, the terminal fitting and the flat conductor can be connected witha high contact pressure.

[0010] The zigzag configuration defines ridges that may extend at anangle different from 0° or 180° to an extension direction of the flatconductor, and preferably substantially normal to the extensiondirection. Thus, resistance against a force to withdraw the flatconductor from the terminal fitting is high compared to a terminalfitting with ridges that extend parallel to the extension of the flatconductor.

[0011] The invention also is directed to a terminal connection apparatusfor connecting a flat conductor and a terminal fitting. The apparatuscomprises arranging means for arranging at least one pair of squeezingplates of the terminal fitting to oppose each other at opposed sides ofan exposed conductor near an end of the flat conductor. The apparatusalso comprises deformation means for deforming a portion of thesqueezing plates into a zigzag configuration and for squeezing orsandwiching the exposed end portion of the flat conductor by thesqueezing plates.

[0012] The deformation means may comprise press dies with recessed andprojected portions for forming the zigzag configuration. The deformationmeans preferably deforms the squeezing plates into the zigzagconfiguration while the squeezing plates squeeze the exposed end of theflat conductor.

[0013] The invention also relates to a terminal fitting for connectionwith a flat conductor. The terminal fitting comprises at least twosqueezing plates that can be opposed to each other at the front and rearsides of an exposed portion of a conductive path of the flat conductor.The squeezing plates comprise a portion with a zigzag configuration thatextends at least partly in a direction normal to the plane that containsthe exposed portion of the conductive part.

[0014] The terminal fitting may also comprise at least one holdingportion on at least one of the squeezing plates for holding thesqueezing plates so that the exposed conductors of the flat conductorremain squeezed between the squeezing plates and under high contactpressure.

[0015] The squeezing plates are connected by a bent portion that isfolded back at least twice. Additionally, the squeezing plates can berotated relative to one another about the bent portion.

[0016] These and other objects, features and advantages of the presentinvention will become apparent upon reading of the following detaileddescription of preferred embodiments and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017]FIG. 1 is a perspective view showing a state before a terminalfitting and a FFC are connected according to one embodiment of theinvention.

[0018]FIG. 2 is a development of the terminal fitting.

[0019]FIG. 3 is a side view partly in section showing a state before theterminal fitting and the FFC are connected.

[0020]FIG. 4 is a side view partly in section showing a state before theterminal fitting is pressed by press dies.

[0021]FIG. 5 is a side view partly in section showing a state after theterminal fitting and the FFC are connected.

[0022]FIG. 6 is a perspective view after the terminal fitting and theFFC are connected.

[0023]FIG. 7 is a perspective view showing a state before a terminalfitting and a FFC are connected according to a prior art method.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0024] A terminal fitting in accordance with the invention is identifiedby the numeral 20 in FIGS. 1-6, and is used with a substantiallyflexible flat cable 10 (hereinafter referred to as FFC 10). The FFC 10has a plurality of substantially parallel conductors 11, only one ofwhich is shown in FIG. 1. Insulation sheets 12 are adhered to the frontand rear surfaces of the conductors 11 so that the FFC 10 defines aflexible ribbon shape. The insulation sheet 12 on the front surface ofthe conductors 11 is stripped away for a specified distance from the endof the FFC 10. Thus, the front surfaces of the conductors 11 are exposedadjacent the end of the FFC 10.

[0025] The terminal fitting 20 is preferably a male terminal fitting andis formed e.g. by processing a conductive metallic plate material by apress. More particularly, the terminal fitting 20 has a tab 21 that isconfigured to be mated with a mating female terminal fitting (notshown). A first squeezing plate 22 extends from the rear end of the tab21. A second squeezing plate 23 initially is substantially parallel tothe first squeezing plate 22 and is connected to the first squeezingplate 22 by a bent portion 24 that projects sideways from the rear endof the tab 21, as shown in FIG. 2. The bent portion 24 is folded backtwice during the press-forming of the terminal fitting 20 so that thefirst and second squeezing plates 22 and 23 oppose each other. Thus, thesecond squeezing plate 23 can be rotated about the bent portion 24 sothat the rear end (right side in FIG. 2) of the second squeezing plate23 can be moved towards or away from the rear end of the first squeezingplate 22 (refer to FIGS. 1 and 6). Accordingly, the space between theopposed first and second squeezing plates 22 and 23 can be opened andclosed.

[0026] The length of the first and second squeezing plates 22, 23 issubstantially equal to the length of the exposed portions of theconductive paths 11 of the FFC 10. Additionally, the widths of the firstand second squeezing plates 22, 23 are slightly wider than the widths ofthe conductors 11.

[0027] Crimping pieces 26 are formed at opposite edges of the rear endof the first squeezing plate 22 and extend toward the second squeezingplate 23. The upper ends of the crimping pieces 26 are formed into edgesthat are sufficiently sharp to make cuts in the FFC 10. The crimpingpieces 26 preferably are spaced by a distance greater than the width ofthe corresponding exposed portion of the conductor 11. The two crimpingpieces 26 are substantially opposed to each other in the illustratedembodiment. However, the crimping pieces 26 may be displaced withrespect to each other along the longitudinal direction of the firstsqueezing plate 22.

[0028] The squeezing plates 22 and 23 of the terminal fitting 20 areleft open, as shown in FIGS. 1 and 3, and an end portion of the FFC 10with the exposed conductors 11 is inserted between the squeezing plates22 and 23.

[0029] Next, as shown in FIGS. 4 and 5, the terminal fitting 20 ispressed by press dies 30, 31 from above and below the squeezing plates22, 23. Recessed/projected portions 32, 33 are provided on the facingsurfaces of the upper and lower press dies 30, 31. Therecessed/projected portion 32 includes a large recess 32A between twosmall projections 32B, while the recessed/projected portion 33 includesa large projection 33A between two small recesses 33B. Therecessed/projected portions 32, 33 are substantially complementary toeach other to avoid displacement when the terminal fitting 20 ispressed.

[0030] The ridges of the recessed/projected portions 32, 33 preferablyextend substantially perpendicular to the longitudinal direction of theterminal fitting 20. Thus, when the terminal fitting 20 and the FFC 10are connected, the squeezing plates 22, 23 are formed into a zigzagconfiguration 27 with ridges that extend normal to the extension of theFFC 10. The zigzag configuration 27 extends out of the plane of theexposed conductors 11. More particularly, interaction with the pressingdies 30 and 31 causes the squeezing plates 22 and 23 and the FFC 10 toassume a zigzag configuration 27, as shown in FIG. 6. The zigzagconfiguration 27 is illustrated with sharp ridges. However roundedridges may also be possible. In the latter case, the recesses 32A and33B and projections 33A and 32B are formed accordingly.

[0031] The pressing of the terminal fitting 20 and the FFC 10 by thepress dies 30, 31 causes the crimping pieces 26 on the first squeezingplate 22 to penetrate through the insulation sheet 12 at opposite sidesof the conductor 11 to reach the front side. The pressing operationdeforms the squeezing plates 22, 23 and squeezes the conductive path 11to define the zigzag configuration 27. Further, the pressing operationbends the crimping pieces 26 inwardly and into crimped connection withopposite side edges at the rear end of the second squeezing plate 23. Asa result, the squeezing plates 22 and 23 are connected in their closedstate with the exposed portion of the conductive path 11 squeezedtherebetween. Thus, the terminal fitting 20 and the FFC 10 are connectedwith a high contact pressure, and a stable electrical performance isachieved.

[0032] The terminal fittings 20 and portions of the FFC 10 connected tothe terminal fitting 20 can be accommodated in cavities of a connectorhousing (not shown). In this state, a backward pulling force that actsin the direction of the arrow F in FIG. 5 may be exerted on the FFC 10.In this embodiment, the zigzag configuration 27 has ridges that extendsubstantially normal to the extension of the FFC 10. Thus, resistanceagainst a force acting in the direction to withdraw the FFC 10 from theterminal fitting 20 is increased as compared, for example, to a casewhere the ridges extend parallel to the extension direction of the FFC10.

[0033] The present invention is not limited to the above embodiment. Forexample, following embodiments are also embraced by the technical scopeof the present invention as defined by the claims. Further, thetechnical scope of the present invention is extended to the scope ofequivalents as defined by the claims.

[0034] Only one insulation sheet 12 is stripped in the foregoingembodiment. However, both insulation sheets 12 may be stripped accordingto the present invention.

[0035] Although the terminal fitting 20 is a male terminal fitting inthe foregoing embodiment, the present invention may be applied to afemale terminal fitting.

[0036] The FFC 10 is used in the foregoing embodiment. However, the flatconductor is not limited to the FFC according to the present invention.A flexible printed circuit board or the like also may be used.

[0037] Although the crimping pieces 26 are formed at the opposite sidesof the first squeezing plate 22 in the foregoing embodiment, the holdingportions need not be provided at the opposite sides according to thepresent invention. It may be sufficient to provide at least one holdingportion. Further, the holding portion is not limited to the crimpingpiece 26, but any holding portion may be adopted provided that it canhold a squeezed state of the flat conductor by the two squeezing plates.For example, the holding portion may be a hook projecting from onesqueezing plate toward the other.

What is claimed is:
 1. A method for connecting a flat conductor (10) anda terminal fitting (20), the method comprising the steps of: exposing aportion of a conductor (11) adjacent an end of the flat conductor (10),arranging the exposed conductor of the flat conductor (10) betweenopposed squeezing plates (22, 23) of the terminal fitting (20), anddeforming the squeezing plates (22, 23) into a zigzag configuration(27), such that the exposed conductor of the flat conductor (11) issqueezed by the squeezing plates (22, 23).
 2. A method according toclaim 1 , wherein the squeezing plates (22, 23) are deformed into thezigzag configuration (27) with the exposed conductor of the flatconductor (10) being squeezed by the squeezing plates (22, 23).
 3. Amethod according to claim 1 , wherein at least one holding portion (26)is provided on at least one (21) of the squeezing plates (22, 23), themethod comprising deforming the holding portion (26) for holding thesqueezing plates (22, 23) such that the exposed end portion of the flatconductor (11) is squeezed between the squeezing plates (22, 23).
 4. Amethod according to claim 3 , wherein the holding portion (26) on onesqueezing plate (21) is bent inwardly and crimped substantially intoconnection with the other squeezing plate (22).
 5. A method according toclaim 1 , wherein the zigzag configuration (27) is formed such thatridges extend substantially normal to an extension direction of the flatconductor (10).
 6. A terminal connection apparatus for connecting a flatconductor (10) and a terminal fitting (20), comprising: arranging meansfor arranging at least one pair of squeezing plates (22, 23) of theterminal fitting (20) to oppose front and rear sides of an exposedconductor (11) at an end portion of the flat conductor (10), anddeformation means (30, 31) for deforming a portion of the squeezingplates (22, 23) into a zigzag configuration (27) and for squeezing theexposed end portion of the flat conductor (11) by the squeezing plates(22, 23).
 7. A terminal connection apparatus according to claim 6 ,wherein the deformation means (30, 31) comprises two press dies (30, 31)having formed recessed and projected portions (32, 33) for forming thezigzag configuration (27).
 8. A terminal connection apparatus accordingto claim 8 , wherein the deformation means (30, 31) is operative fordeforming the squeezing plates (22, 23) into the zigzag configuration(27) while the exposed end portion of the flat conductor (11) is beingsqueezed by the squeezing plates (22, 23).
 9. A terminal fitting (20)for connection with a flat conductor (10), comprising first and secondsqueezing plates (22, 23) opposed to front and rear sides of an exposedportion of a conductor (11) of the flat conductor (10), wherein thesqueezing plates (22, 23) comprise a portion having a zigzagconfiguration (27) at least partly extending in a direction normal to aplane containing the exposed portion of the conductor (11).
 10. Aterminal fitting according to claim 9 , wherein at least one holdingportion (26) is provided on at least one (21) of the squeezing plates(22, 23) for holding the squeezing plates (22, 23) such that the exposedend portion of the flat conductor (11) is squeezed between the squeezingplates (22, 23).
 11. A terminal fitting according to claim 10 , whereinthe squeezing plates (22, 23) are connected to each other by a bentportion (24) that is folded back at least twice, the squeezing plates(22, 23) being movable toward each other by rotating at least one of thesqueezing plates (22) about the bent portion (24).